This project uses different systems to develop objective and subjective methods to monitor and document opacities in the human lens. We are actively recruiting patients with and without cataracts for reproducibility studies on the objective system-the Scheimpflug cameras (Zeiss and Topcon), retroillumination camera (Neitz), specular microscope (Keeler) and laser light-scattering spectroscope (Kowa). Tests of other systems will use sound (ultrasonography) and nuclear magnetic resonance (magnetic resonance imaging). Our study of subjective systems or methods such as the effects of cataracts on visual perception, contrast sensitivity, and glare may be useful in identifying additional parameters for monitoring cataract presence, progression, or regression.